// UUID: 3daa5fb8-3825-4767-8910-9a8bf8a5a514
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
	ll n;
    cin >> n;
    vector <pair<ll, ll>> szamok(n);
    for ( ll i = 0; i < n; i++ ){
        cin >> szamok[i].first;
        szamok[i].second = i+1;
    }
    sort(szamok.begin(), szamok.end());
    ll k =  INT_MAX, j = 0;
    for ( auto i = 0; i < n; i++ ){
        if ( j - k < j - szamok[i].second ){
            k = szamok[i].second;
        }
        else j = max( j, szamok[i].second );
    }
    if ( j == 0 ) cout << -1 << "\n";
    else cout << k << " " << j << "\n";
}